linux/drivers/nfc/microread/i2c.c
Uwe Kleine-König ed5c2f5fd1 i2c: Make remove callback return void
The value returned by an i2c driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marek Behún <kabel@kernel.org> # for leds-turris-omnia
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Machata <petrm@nvidia.com> # for mlxsw
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> # for surface3_power
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> # for bmc150-accel-i2c + kxcjk-1013
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> # for media/* + staging/media/*
Acked-by: Miguel Ojeda <ojeda@kernel.org> # for auxdisplay/ht16k33 + auxdisplay/lcd2s
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # for versaclock5
Reviewed-by: Ajay Gupta <ajayg@nvidia.com> # for ucsi_ccg
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Acked-by: Peter Rosin <peda@axentia.se> # for i2c-mux-*, max9860
Acked-by: Adrien Grassein <adrien.grassein@gmail.com> # for lontium-lt8912b
Reviewed-by: Jean Delvare <jdelvare@suse.de> # for hwmon, i2c-core and i2c/muxes
Acked-by: Corey Minyard <cminyard@mvista.com> # for IPMI
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com> # for drivers/power
Acked-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2022-08-16 12:46:26 +02:00

299 lines
6.0 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* HCI based Driver for Inside Secure microread NFC Chip - i2c layer
*
* Copyright (C) 2013 Intel Corporation. All rights reserved.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/nfc.h>
#include <net/nfc/hci.h>
#include <net/nfc/llc.h>
#include "microread.h"
#define MICROREAD_I2C_DRIVER_NAME "microread"
#define MICROREAD_I2C_FRAME_HEADROOM 1
#define MICROREAD_I2C_FRAME_TAILROOM 1
/* framing in HCI mode */
#define MICROREAD_I2C_LLC_LEN 1
#define MICROREAD_I2C_LLC_CRC 1
#define MICROREAD_I2C_LLC_LEN_CRC (MICROREAD_I2C_LLC_LEN + \
MICROREAD_I2C_LLC_CRC)
#define MICROREAD_I2C_LLC_MIN_SIZE (1 + MICROREAD_I2C_LLC_LEN_CRC)
#define MICROREAD_I2C_LLC_MAX_PAYLOAD 29
#define MICROREAD_I2C_LLC_MAX_SIZE (MICROREAD_I2C_LLC_LEN_CRC + 1 + \
MICROREAD_I2C_LLC_MAX_PAYLOAD)
struct microread_i2c_phy {
struct i2c_client *i2c_dev;
struct nfc_hci_dev *hdev;
int hard_fault; /*
* < 0 if hardware error occured (e.g. i2c err)
* and prevents normal operation.
*/
};
#define I2C_DUMP_SKB(info, skb) \
do { \
pr_debug("%s:\n", info); \
print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \
16, 1, (skb)->data, (skb)->len, 0); \
} while (0)
static void microread_i2c_add_len_crc(struct sk_buff *skb)
{
int i;
u8 crc = 0;
int len;
len = skb->len;
*(u8 *)skb_push(skb, 1) = len;
for (i = 0; i < skb->len; i++)
crc = crc ^ skb->data[i];
skb_put_u8(skb, crc);
}
static void microread_i2c_remove_len_crc(struct sk_buff *skb)
{
skb_pull(skb, MICROREAD_I2C_FRAME_HEADROOM);
skb_trim(skb, MICROREAD_I2C_FRAME_TAILROOM);
}
static int check_crc(const struct sk_buff *skb)
{
int i;
u8 crc = 0;
for (i = 0; i < skb->len - 1; i++)
crc = crc ^ skb->data[i];
if (crc != skb->data[skb->len-1]) {
pr_err("CRC error 0x%x != 0x%x\n", crc, skb->data[skb->len-1]);
pr_info("%s: BAD CRC\n", __func__);
return -EPERM;
}
return 0;
}
static int microread_i2c_enable(void *phy_id)
{
return 0;
}
static void microread_i2c_disable(void *phy_id)
{
return;
}
static int microread_i2c_write(void *phy_id, struct sk_buff *skb)
{
int r;
struct microread_i2c_phy *phy = phy_id;
struct i2c_client *client = phy->i2c_dev;
if (phy->hard_fault != 0)
return phy->hard_fault;
usleep_range(3000, 6000);
microread_i2c_add_len_crc(skb);
I2C_DUMP_SKB("i2c frame written", skb);
r = i2c_master_send(client, skb->data, skb->len);
if (r == -EREMOTEIO) { /* Retry, chip was in standby */
usleep_range(6000, 10000);
r = i2c_master_send(client, skb->data, skb->len);
}
if (r >= 0) {
if (r != skb->len)
r = -EREMOTEIO;
else
r = 0;
}
microread_i2c_remove_len_crc(skb);
return r;
}
static int microread_i2c_read(struct microread_i2c_phy *phy,
struct sk_buff **skb)
{
int r;
u8 len;
u8 tmp[MICROREAD_I2C_LLC_MAX_SIZE - 1];
struct i2c_client *client = phy->i2c_dev;
r = i2c_master_recv(client, &len, 1);
if (r != 1) {
nfc_err(&client->dev, "cannot read len byte\n");
return -EREMOTEIO;
}
if ((len < MICROREAD_I2C_LLC_MIN_SIZE) ||
(len > MICROREAD_I2C_LLC_MAX_SIZE)) {
nfc_err(&client->dev, "invalid len byte\n");
r = -EBADMSG;
goto flush;
}
*skb = alloc_skb(1 + len, GFP_KERNEL);
if (*skb == NULL) {
r = -ENOMEM;
goto flush;
}
skb_put_u8(*skb, len);
r = i2c_master_recv(client, skb_put(*skb, len), len);
if (r != len) {
kfree_skb(*skb);
return -EREMOTEIO;
}
I2C_DUMP_SKB("cc frame read", *skb);
r = check_crc(*skb);
if (r != 0) {
kfree_skb(*skb);
r = -EBADMSG;
goto flush;
}
skb_pull(*skb, 1);
skb_trim(*skb, (*skb)->len - MICROREAD_I2C_FRAME_TAILROOM);
usleep_range(3000, 6000);
return 0;
flush:
if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0)
r = -EREMOTEIO;
usleep_range(3000, 6000);
return r;
}
static irqreturn_t microread_i2c_irq_thread_fn(int irq, void *phy_id)
{
struct microread_i2c_phy *phy = phy_id;
struct sk_buff *skb = NULL;
int r;
if (!phy || irq != phy->i2c_dev->irq) {
WARN_ON_ONCE(1);
return IRQ_NONE;
}
if (phy->hard_fault != 0)
return IRQ_HANDLED;
r = microread_i2c_read(phy, &skb);
if (r == -EREMOTEIO) {
phy->hard_fault = r;
nfc_hci_recv_frame(phy->hdev, NULL);
return IRQ_HANDLED;
} else if ((r == -ENOMEM) || (r == -EBADMSG)) {
return IRQ_HANDLED;
}
nfc_hci_recv_frame(phy->hdev, skb);
return IRQ_HANDLED;
}
static const struct nfc_phy_ops i2c_phy_ops = {
.write = microread_i2c_write,
.enable = microread_i2c_enable,
.disable = microread_i2c_disable,
};
static int microread_i2c_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct microread_i2c_phy *phy;
int r;
phy = devm_kzalloc(&client->dev, sizeof(struct microread_i2c_phy),
GFP_KERNEL);
if (!phy)
return -ENOMEM;
i2c_set_clientdata(client, phy);
phy->i2c_dev = client;
r = request_threaded_irq(client->irq, NULL, microread_i2c_irq_thread_fn,
IRQF_TRIGGER_RISING | IRQF_ONESHOT,
MICROREAD_I2C_DRIVER_NAME, phy);
if (r) {
nfc_err(&client->dev, "Unable to register IRQ handler\n");
return r;
}
r = microread_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME,
MICROREAD_I2C_FRAME_HEADROOM,
MICROREAD_I2C_FRAME_TAILROOM,
MICROREAD_I2C_LLC_MAX_PAYLOAD, &phy->hdev);
if (r < 0)
goto err_irq;
return 0;
err_irq:
free_irq(client->irq, phy);
return r;
}
static void microread_i2c_remove(struct i2c_client *client)
{
struct microread_i2c_phy *phy = i2c_get_clientdata(client);
microread_remove(phy->hdev);
free_irq(client->irq, phy);
}
static const struct i2c_device_id microread_i2c_id[] = {
{ MICROREAD_I2C_DRIVER_NAME, 0},
{ }
};
MODULE_DEVICE_TABLE(i2c, microread_i2c_id);
static struct i2c_driver microread_i2c_driver = {
.driver = {
.name = MICROREAD_I2C_DRIVER_NAME,
},
.probe = microread_i2c_probe,
.remove = microread_i2c_remove,
.id_table = microread_i2c_id,
};
module_i2c_driver(microread_i2c_driver);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION(DRIVER_DESC);